Restore the System Lock Screen

Over the last couple of months I have seen in Windows 10 14393.xxx the User Lock Screen become the Default Lock Screen. I have not found any way to restore the Default Lock Screen to its default (sea cave) image. I have checked in C:\ProgramData\Microsoft\Windows\SystemData\S-1-5-18\ReadOnly\LockScreen_Z and the sea cave image is the only one there. I have tried sfc /scannow and DISM restorehealth and neither have worked. Has anyone else experienced this issue and if so have you found a way to restore the Default Lock Screen to its default? It may a registry entry that has become corrupt or that is set incorrectly. I simply do not know what causes this to happen or how to fix it once it does.

Hi, I believe you will find that image here:
C:\Windows\Web\Screen

Explanation of some aspects of the difference between the default lock screen (seen after booting the PC) and the lock screen seen otherwise:
How to change default lock screen image in Windows 10

Easy way to change the default lock screen using a reliable free tweaker by an expert:

Thanks for responding. You are correct about the sea cave image appearing in C:\Windows\Web\Screen; however MS does something with this image before using it for the Default Lock Screen. Something about not dimmed. I do not understand what that is about, nevertheless I tried this Tweaker when I first encountered my issue and it did not work. Perhaps I will give it another shot when the issue appears again. Currently I am not experiencing the issue because I restored a Macrium image that was created before the issue showed up. So far this has been my only fix for this issue.